It is now well accepted that submersible automated pool cleaning devices, such as self propelled pool cleaning vehicles are essential to the proper maintenance of a pool, whether the pool be above or below ground. The typical vehicle includes a housing and drive members. The drive members attach to the housing usually through connection to a bottom frame. Drive members have, in the past, included wheels driven by a motor stored in the housing. The past vehicle have included two and four wheel drive vehicles. Additionally, past vehicles have included those which are driven by a belt or endless loop track. The track wraps around the drive and/or idler wheels or rollers.
It will be appreciated that a vehicle may also have some combination of wheels and/or rollers and the vehicle may also be a two or four-wheel drive vehicle. The endless loop track may be fitted over any combination of two or four wheel drive vehicles.
Such tracks have been found to be an effective means for moving the vehicle around the surface of the pool while the vehicle is submerged. The track is placed over the drive wheels and/or rollers. In order to move the vehicle, there must be sufficient tension to provide enough torque to move the track through the drive wheels or rollers.
As is well understood, the track is generally flat in cross section. Thus, the challenge for vehicles using such tracks is to hold the track in place without slipping laterally across the track while the vehicle is in motion. Prior vehicles have included a series of alligators across the track. The interior surface of such prior art vehicles includes a series of such alligators which engage the drive wheels for movement of the vehicle.
As with all submersibles, they must operate in a wet environment. Consequently, greater tension is required than in a wet environment. The higher the belt tension, the shorter both the belt life and the motor life.
It is known that by incorporating additional idlers adjacent to the drive wheel additional friction is exerted on the drive wheels and the belt. Thus, the torque is increased as a result of the additional friction. However, the increased torque comes at the expense of increased stress on the drive wheels and the supporting bracket for the drive members. Additionally, the belt still loses traction even with the alligators and additional idler wheels. Thus the original issue remains unresolved.
An additional known advantage of the track is that it overlaps the drive and idlers wheels. Typically, the drive and idlers wheels are made from a high impact and very strong plastic. Without a drive belt, the wheels themselves tend to bump or even crash into the vertical sidewalls of the pool or the pool stairs. Repeated striking of such surfaces can cause damage to not only the vehicle, but to the pool itself. By using a track, the contact between the pool and the vehicle is limited to the track itself. Typically, the track is made from softer material than the hard plastic of the wheels.
What is needed is a submersible automated pool cleaning vehicle which can take advantage of the track drive without suffering losses of torque or early part failure. The submersible vehicle in accordance with this invention provides a track drive which does not create additional tension causing drive members and structures supporting drive members to fail prematurely. Additionally, the submersible vehicle in accordance with this invention provides superior traction capabilities for the vehicle as it travels about the pool surface without damaging the stairs and vertical surfaces of the pool.